With the broad commercialization of personal computers, a wide range of consumers covering children to middle-aged and senior adults have begun to actively use the Internet, multimedia, etc. via the personal computers. The reason personal computers became so familiar to the wide range of consumers is because the operating system (OS) based on GUI (Graphical User Interface) is currently adopted in almost all computers. Namely, owing to the GUI, the user can easily operate the personal computer by using a pointing device such as a mouse while looking at the display. Therefore, occasions, in which the user is required to perform input via the keyboard (hereinafter referred to as “key input”), have decreased substantially than with a conventional OS based on characters, which in turn makes the personal computer more user-friendly even to a user who is not very good at the key input.
Nevertheless, it is not possible to perform all the operations only via the mouse. For example, the character (letter) input is essential upon generating an email document to be sent by using e-mail software or upon generating a document by using word processing software. Among character input devices, keyboard devices are the most commonly used input devices and are included in almost all the personal computers as standard equipment.
There are several types of key arrangements on a keyboard device, namely arrangement of keys via which the alphabet and symbols are inputted. In English-speaking countries, the so-called “QWERTY” arrangement is the most widely adopted arrangement. The QWERTY arrangement was made for early types of mechanical typewriters by intentionally arranging the typebars for frequently used characters at left-right positions away from one another because in the early mechanical typewriters when such frequently used typebars were struck too quickly, the typebars were jammed and consequently broken. In the French-speaking countries, the “AZERTY” arrangement is used in which the arrangement of the letters “Q” and “W” in the QWERTY arrangement are interchanged for that of the letters “A” and “Z”, respectively. In the German-speaking countries, the “QWERTZ” arrangement is used in which the arrangement of the letter “Z” is interchanged for that of the letter “Y” in the QWERTY arrangement. In addition to those described above, for example, the “Dvorak” arrangement developed based on the character frequency in the English language is also used. In any of these key arrangements, there is no apparent rule by which the keys are arranged, and the task of memorizing all the uninteresting or irregular key arrangements is hard and burdensome particularly for a beginner user, which in turn becomes one of the main factors for discouraging the beginner user from inputting (key-typing) via the keyboard.
In addition, a user, who is not accustomed to the key-typing, often types with a self-taught typing method such as a so-called one-fingered or two-fingered typing method for typing using only one or both of the index fingers. In such a case, every time the user strokes (presses) a key, the user must look at the letter engraved or printed on the key to confirm whether or not the right key is being stroked. Therefore, this method has disadvantages that typing speed is slow. In addition, since the user must look alternately at the display and the keyboard, the flow of thought is interrupted. Therefore, the technique of the so-called touch typing (blind typing) requiring the use of all the fingers of both hands without looking at the keyboard is essential to correct and quick typing.
There are many commercially available typing-tutor softwares for learning touch typing. Although many users attempt to practice touch typing by using such softwares, the majority of the users give up before learning touch typing. That is, even a beginner user can touch type by using such a tutor software because the software is devised with functions, for example, for showing a keyboard image on the display while the user is practicing touch typing by using the software, thereby enabling the user to type without looking at the keyboard. However, once the user quits the software, the functions become unavailable to the user. Therefore, when the user is still practicing touch typing but a document must be generated by touch typing, the user must touch type by oneself, which often results in the user reverting back to the self-taught typing method. In such a manner, the majority of users spends time between touch-typing practice and the self-taught typing repeatedly and eventually reverts back to the self-taught typing. The tutor software is originally intended that the user preferably uses the software and keeps practicing until the user completely masters touch typing, but many of the users are not patient enough to do so.
In view of the above situation, there is proposed the usage of a keyboard device or a keyboard cover adopted for practicing touch typing, rather than practicing touch typing by using software only. For example, Japanese Patent Application laid-open No. 2002-091663 discloses a keyboard cover which is provided with projections partitioning typing areas designated for the fingers respectively or a keyboard cover in which areas designated for the fingers respectively are colored differently (color-differentiated), for the purpose of performing touch typing with the fingers placed at the correct positions.